Harmonic signaling for party-lines.



PATENTED JULY 31, 1906.

W. W. DEAN. HARMONIG SIGNALING FOR PARTY-LINES.

' APPLICATION FILED AUG.9. I905.

03: A dawn 6 0.9% mm}: 5% E i M w w w AW- NITED STATES PATENT OFFICE.

WILLIAM W. DEAN, or ELYRIA, OHIO, ASSIGNOR TO THE DEAN ELECTRICCOMPANY,- OF ELYRIA, OHIO, A CORPORATION OF OHIO.

- HARMQNIO SIGNALING FOR PARTY- -LINES.

I p Specification of Letters Patent.

r mmed July 31. 1906.

Application 518a August 9,1905. Serial No. 273.456.

Toll/ll. wl z om it may concern:

Be it known that LiWI LLLaM W. DEAN, a citizen of the United States,residing at Elyria, in the county of, Lorain and State of Ohio, haveinvented certain new and useful Im rovements in Harmonic Signaling forPartyines', of which the following is a specifica- -tion, referenceBeing had therein to the accofipanying drawing.

-r o y invention relates to telephone systems,

and particularly-to What is known as harmomo si aling for arty-lines.

. Accordiiig to metlibds-heretofore employed f ench of severalsubscribers stations connect- I 5 ed to the same line has been equi pedwith a signaling device or ringer adapts to respond to a 'given-frequenconly o si" aling-current. Atthe centrai ofiice seversd generators I havebeen provided, usually four in number, so since the number of stationson one line in practice is generally limited to that number. .Of coursethese generators are not usually i built as separate machines, but formparts of onemachine, whose speed is rendered fairly .225 constant bymeans of govermng devices e whichlit is unnecessary here todescribe. Ac-.J-cordiug to some systems the ringer-armatures .at the substation,which constitute reeds, are.

tuned so as to' belin exact accord with the several i'difl'erentcurrents'by which they are to be respect velyactuated. Accordihg toother systems the ringers are overtuned or undertuned, according totheird-esign and thejexigencies of the case; but my present inventionisnot limited to any of tliese' in articular,'but is, in; fact,applicable to all oftl iem, since its aim is to correct a defeet foundin them an; i 7 'In all harmonicpartylinesystems I have 40 found byexperiment that while there is race tically no tendency for a currentof, big frequency toaffect the bells on the line. which *are tunedtorespond to lower frequencies the reverse is not true, currents of lowfrequenc showinga strong't'endenc' to affect the bel s or. ringerswhichlare tune tores ond to high frequencies only. Ihave found 1tpossible to overoon 9 this tendency and to effectively limit eachringing-current to its own tuned 5o bell by windmg. generatorsso that threpective outputs shall be of diversevo ages. {find it veryeffective tomake a-low-frequency generator of lo'w'voltage and a, highcurrents.

quencybells, which are always har est to ring, can be tuned and adjustedmore delifre uency generator'of hi h voltage. It isevi ent that by thismethod they hi h-fre-v cately than otherwise would be possible withoutbeing affected by thelow-frequeney Inorder to still further increase themargin of selection, I als0 find it expedient to makethecondensers oflow-frequency bells of larger capacitythan the others, those for the bigest-frequency bells being, in fact, of very small capacit My inventionis illilstrated' in the accompanying drawing,.which is a diagram of apolystation-line and the central office apparatus .throu h and by whichany station on the line can e selected andrun I In the drawing, A, A, A,and A? are sub scribers stationsall connected to :the same pair ofline-Wires 1.2. At eachsub'scribers station I provide the usualtransmitter T, re ceiver R, switch-hook H, and'whatever other apparatusmay be reguired addition t}? the enser ave s own ringer Q and the. conthe telephone setandswitch-hook at station A only, their inclusion at'e'achof the other stations being understood.

At the central office the line-wires terminate, respectively, in thesprings j j of the 'jack J, which may be a single hne 'ackiofa simple ortransverse boardor may e taken as the type of multiple jacks on amultiple switchboard. In the lattercase'a test+thima ble 7' would be"required for each jackyand I have illustrated it for thatreason. Thelin'esignal L is shown as a drop-annunciator, oo'nnected to the linethrough .cut ofi contaots in the jack, itsv circuit 1920 including asource; of signaling-current B. Y

Cooperating with-the jack and intended to estabhsh connection betweenthe subscribers i p m P, WlJlCh lshere supposedto be the cal mgline andother lines or circuitsfis the.

plug of a pair whose corresponding contacts are connectedtogeth'er throuh cord conduc- I' tors '3. to 11 and 4 to'12.- I H ve shown the pluglwith a ta -contact pconnected to the twm or answering. plugofithev pair.my

conductor 3 an the sleeve-contact con- -nected' to theconductor 4. Thecon uctors a 11 and 12are therefore supposed to besimilarly connected.to the. tap and'sleeve' of thel nd G, "and there the caliingillustrated". rovide four selective ringing: e h s. t wh at any partlcuar one of the four stations A 1N4 At Each of these l ingvkcys has a r ofs m 8 with front-a H back. ntacts. hse o, the y K are 1r and n th ir nomal condition of dream they rest upon th i ont contacts connected o thndu t r 5 and 6, wluchpass then e to the snlicgsk. and-k of the key Kthese in turn normally resting, upon front 300M100 ,can-

nested. thfo -Wes 7 and 8 to the springs it-26m e -oft keyK, whlchnot-really rests scc sntacts diss cted tbrou hwircs 9 and ze m si k d s"its s e! rest a ts-c t see-springs 1 tc'th conductors ll and 12. E

' eys is pr vided with an actuatingbntton or layer with-a cam, whichupon actuation of. the I 'cles, I double the capacity,

button or. level B ts to spread apart the -springs, breaking. thecommotion between per second.

conductors 3 .4 and 11 "12 and establishing a conncctlon f om theconductors .3 4 to onc'of the generators. Thus u on actuating the.button orlever' of key K t e springs k and k" are carried'from theterminals of wires 5 and Q close the circuit for generator G, which maybe traced as follows: on the one ide from the I generator (3; and bgwires '17 and 18 to e other side from the sleeve 12 through con- 1'.ln'ctor 4 to the spring k and thence direct to the ground- The Iiluhaving been inserted the J J en t e ey K is thus actuated, current fromthe generator G will pass out from the line-wires 1 2 to actuate theball at he corresponding station.

The ringers Q, Q, Q, and Q? at the sta- A N, respectively, are designedto respond to and be actuated by currents of the following frequencies:for ringer Q, can

rent at 66.6 -cycles; for ringer-Q, current at 'fiftycycles; fcrnngcrQ,currcnt at 33.3 cy-- cles, andfor ringer Q current at 16.6 cycles Gare wound and rents of the four. that is, gsneratorizragives current at66.6 cycles, G current at ty cyclcafil current at 33.3 cycles-and G?current at 16.6; cycles.-

There is nothing essentially novel in the sfistem.thue far described;With. some s ght modifications it might be taken as a type of that classof systems familiar to telephone engineers under the name of f run so asto. produce. curconnected sell of the this one-fourth of a nucrofarad.The rlfrilfgter Q tip 12 through conductor 3 to the springk, thence tothe.

the ground at g; on.

'scri tion that t since I have cut down the generators .G, "G', G?

frequencies mentioned-;

however, may now be understood and will be described as ap liedtoptheforegoing, It

con' sts essent aly 1ng1 the generators Gr, El, and G3 $1 101! 'pecu a wsdi a-srbo h the they w produce theirrespective current at diverseVoltages ae'wsll as of diverse frequencies. Thus' the "generator-G,Idesign to produce current ata Voltage ofitwo hundred, generator G atone hundred and fifty, generator 43: at one hundred and thehigh-freqncncy generators also high voltsfif machines, .relatiyelyspeaking and the w frsquency generators I {no a low-voltage machinos.0011351101111 1 1% m ysind the nngers Q Q Q Q of (ii crent resistance,or, as I have shown m the I preferably make the condenser's in t eringer branches of diverse copacitie's. The ringer Q at station'A beingtuned respond to current at a'frequency of 66.6 cycles per second, whichis the marrimnm employed in the system, I include 1n ringerbranchthe'rninimum canacity of being tuned to respond to current at ycymakmgit oneiarities of speed halfof a mierofarad. For ringer Q, I againdouble'the capacity, making it one micrsfared, and for ringer Q Iprovidetwo microfarads. The condensers 0, .C, .0, and .0 haveprogressivslyiucreasing capacitics therefore, the largest capacity .0corresponding to the lowest quency and the lowest-voltage current whichis thrown out by the generator (3?. nregolng'de- It Will be apfiarcntfrom the are will be little or no chance for eakagc andconsequent-interference by low-fro uency current through the high-fro.-

quency ranches at stationsAA. The h frequency bells are the hardest toor mechanical as well as electrical reasons, and capacity asmallfraction and the voltage-or pressure of the current also to a smallfraction of the maximum, the freiuency being already a small fractionthereo the amount of leakage transmitted through; the highefrenegligible. Moreover, it wi' be noticedm going down the scale fromstation to station as the capacities and voltages increase th tendencyto interference decreases; 'llhns the system is perfectl symmetrical. Ibelieve I am the first-person to combine thafactors by which enertransmission has heretofore beanseparate -l. imite.cl. -1 Ishallthereficre-claim the" same (madly and wish it .to be distinctlynnderstoodthat all applica tions of'this broad idea; whatever be theirspecific form, and all the mod fications which may be made-therein arccontemplated'by as. withinthescope and purview of my invention.

ncy branch is.

' rent impu ses to any desired frequency at a voltage approximatelyproportionateto the I said signal-receiving devices being tuned toringers connected thereto, a corresponding scribers line and a pluralityof differentlysponding plurality of ringing-generators at one of saidgenerators being adapted to fur nish current of low frequency and atarela- Having thus described my invention, What I claim, and desire toobtain by Letters Iatent, is

1. In a telephone system, the combination of a plurality ofsignal-receiving devices tuned to respond to periodic impulses atdifferent fre uencies', and means to supply curfrequency.

2. In a telephone system, the'combination of a line-circuit and aplurality of signal-receiving devices connected thereto each of respondto a current of a particular frel quency, with sources of current, andmeans to connect one or more of said sources to said circuit, thecurrent from said sources varying not only as to its frequency but as toitsvoltage.

3. In a telephone-exchange system, a party-line and aplurality ofdiflerently-tuned plurality of periodic current-generators, eachfurnishing current of a given frequency and at a voltage approximatelyproportional to the frequency.

4. In a-telephone-exchange system, a subtuned ringers connected thereto,a correthe centr station, adapted to furnish ringing-currents of highand low frequencies, and of high and low voltages, and switching meanswhereby any oneof said generators may be connected to said line.

5. In a telephone-exchange system, a subscribers circuit and a pluralityof stations connected thereto, a ringer at, each station connected tothe circuit and tuned to respond either t9 giigh or low frequencycurrents only, central-o ce switching means and a plurality of selectiveringing-generators adapted to be connected thereby to the subscriberscircuit,

tively low voltage, and another of said generators beingadaptedtofurnish current of high frequency and at a relatively high voltage,whereby the low-frequency current will be unable to objectionably affectthe highfrequency ringers.

6. In a telephone-exchange system, a party-line with a plurality ,ofsubscribers ringers connected thereto, said rihgers being rality ofsources of ringing-current of progressively-increasing frequenciescorrespondmg to those of the ringers, and means to pre- 'vent current ofone frequency from passing pitch, a plurality of generators adapted to'furnish ringing-currents ranging from high to low in frequency, andmeans to regulate the output of the generators according to theirfrequencies by limiting the effective electromotive force impressed onthe line thereby.

9. In a telephone-exchange system, a plurality of tuned bells,rangingfrom high ,to low pitch, a plurality of generators adapted to furnishringing-currents ranging from high to low' in frequency, and means forregulating the amount of effective current from any one generator whichshall pass through each ringer by limiting the effective electromotiveforce impressed on the line thereby.

. 10. In a telephone-exchange system, a subscribers line and a pluralityof harmonic ringers connected thereto,- means for furnishing selectivecurrent for said ringers, a condenser in circuit with each ringer, thecapacities of the condensers being inversely proportionate to thefrequency to whichtheir corresponding ringers are tuned and means tolimit the output of current for each ringer by limiting the effectiveelectromotive force at the ringer terminals.

-11. In a telephone-exchange system, a

party-line and a' plurality of subscribers stations having ringers tunedto progressivelyincreasing frequencies connected to said li'ne,

central-office switching apparatus for said line, and a pluralityofringing-generators furnishing current of progressively-increasingfrequencies at progressively-increasing voltages.

In testimony whereof I affix my signature in presence of two Witnesses.

WILLIAM w. DEAN. Witnesses A. D. THIBBY,

Gno. A. SoovrLLE.

